@misc{indiciae34c7d5d362ed,
  title = {Preliminary geologic map of the Sentinel Peak NE quadrangle, Montezuma County, Colorado},
  author = {E. B. Ekren and F. N. Houser},
  year = {1959},
  doi = {10.3133/mf224},
  url = {https://pubs.usgs.gov/publication/mf224},
  note = {Source identifier: mf224}
}